(a) Field of the Invention
The present invention relates to vehicle anti-theft, and more specifically to a vehicle anti-theft device. When in an anti-theft mode, the vehicle anti-theft device controls the starter battery to only allow a low current output to supply the electric requirements of the vehicle electronic equipment, such as the electronic control unit, vehicle acoustics, and the like, and disables a high current output that would supply and start the vehicle starter motor, thereby preventing the vehicle from being stolen.
(b) Description of the Prior Art
Taiwan Utility Model Publication No. M416829 discloses an anti-theft lithium power battery, comprising a control device installed on the vehicle's lithium power battery, a remote control unit mounted on the vehicle exterior, and a voice broadcaster mounted on the vehicle interior, wherein the remote control unit is used to control the control device.
The control device is assembled from a circuit board, a battery management system mounted on the circuit board, a security system mounted on the circuit board, and at least one alarm system mounted on the circuit board and electrically connected to the security system.
The security system is assembled from a current control circuit, a vibration switch, and a diagnosis circuit. The current control circuit is used to control whether the lithium power battery outputs electric power or not. The vibration switch is used to activate the alarm system when the vehicle vibrates. The diagnosis circuit is controlled by the remote control unit, and decides whether to activate the current control circuit or not. When the current control circuit is activated and the vehicle driver wants to start the vehicle, or the vibration switch has been activated, the alarm system and the voice broadcaster are activated, and at the same time, the current control circuit continues to be activated until the remote control unit, through the diagnosis circuit, cuts off the current control circuit, the alarm system, and the voice broadcaster.
The abstract of Taiwan Utility Model Publication No. M416829 discloses that the security system consists of a current limiting circuit, and activating the current limiting circuit puts the vehicle in a state whereby current is flowing but the vehicle cannot be started. And when the current limiting circuit is activated, and a high current output is needed to start the vehicle, then the alarm system is activated, and the current limiting device continues to be activated.
However, the description in the specification of Taiwan Utility Model Publication No. M416829 does not describe how the technological measures enable disabling the vehicle from starting when the current limiting circuit is activated. And the vehicle starter battery uses an electrical connection between the current outlet terminals of the battery and the vehicle circuitry system to supply electric energy to the vehicle. The current limiting circuit disclosed in Taiwan Utility Model Publication No. M416829 is able to maintain its function to output a low current for use by the vehicle's electronic equipment when in an anti-theft mode, indicating that the battery and the vehicle circuitry system are in a closed circuit state enabling a current to flow. However, the battery can also output a high current to the vehicle through the same current circuit, and thus unable to achieve the effect of disabling the vehicle from starting as recorded in the abstract.
Furthermore, vehicle anti-theft devices of the prior art, including that disclosed in Taiwan Utility Model Publication No. M4168295, use a remote control unit or a chip key to perform an unlock or cancel operation when in an anti-theft mode. However, if the remote control unit or chip key is duplicated by a thief, then the thief is able to use the duplicated remote control unit or chip key to cancel the anti-theft settings and easily drive away the vehicle. Hence, because of the worry that the remote control unit or the chip key has been duplicated, the vehicle owner must visit the supplier and have the anti-theft device installed on the vehicle replaced together with the remote control unit or chip key.